> ## Documentation Index
> Fetch the complete documentation index at: https://cantonfoundation-dpm-import.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# DA.Crypto.Text

> Reference documentation for Daml module DA.Crypto.Text.

<span id="module-da-crypto-text-67266" />

# DA.Crypto.Text

Functions for working with Crypto builtins.

For example, as used to implement CCTP functionality.

## Module Snapshot

<CardGroup cols={2}>
  <Card title="Lifecycle">
    Stable.
  </Card>

  <Card title="Notices">
    Status: `active`
    Introduced in: `3.4.9`
    Removed in: `-`
    Warnings: `0`
    Deprecations: `0`
    Deprecated since: `-`
  </Card>
</CardGroup>

## Data Types

<span id="type-da-crypto-text-byteshex-47880" />

### `type BytesHex`

\= [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

<span id="type-da-crypto-text-publickeyhex-51359" />

### `type PublicKeyHex`

\= [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

A DER formatted public key to be used for ECDSA signature verification

<span id="type-da-crypto-text-signaturehex-12945" />

### `type SignatureHex`

\= [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

A DER formatted SECP256K1 signature

## Typeclasses

<span id="class-da-crypto-text-hastohex-92431" />

### `class HasToHex a`

Methods:

* `toHex` : `a` -> [`BytesHex`](#type-da-crypto-text-byteshex-47880)
  Converts a typed data value into a hex encoded string.

Instances:

* instance [`HasToHex`](#class-da-crypto-text-hastohex-92431) [`Party`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-party-57932)
* instance [`HasToHex`](#class-da-crypto-text-hastohex-92431) [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261)
* instance [`HasToHex`](#class-da-crypto-text-hastohex-92431) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

<span id="class-da-crypto-text-hasfromhex-84972" />

### `class HasFromHex a`

Methods:

* `fromHex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> `a`
  Converts a hex encoded string into a typed data value.

Instances:

* instance [`HasFromHex`](#class-da-crypto-text-hasfromhex-84972) ([`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) [`Party`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-party-57932))
* instance [`HasFromHex`](#class-da-crypto-text-hasfromhex-84972) ([`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261))
* instance [`HasFromHex`](#class-da-crypto-text-hasfromhex-84972) ([`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952))

## Functions

<span id="function-da-crypto-text-ishex-17968" />

### `isHex`

`isHex` : [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

`isHex` is `True` if `t` is not empty and consists only of
hex or hexadecimal characters.

<span id="function-da-crypto-text-sha256-84499" />

### `sha256`

`sha256` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Computes the SHA256 hash of the decoded UTF8 bytes of the `Text`, and returns it in its hex-encoded
form. The hex encoding uses lowercase letters.

<span id="function-da-crypto-text-keccak256-57106" />

### `keccak256`

`keccak256` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Computes the KECCAK256 hash of the UTF8 bytes of the `Text`, and returns it in its hex-encoded
form. The hex encoding uses lowercase letters.

<span id="function-da-crypto-text-secp256k1withvalidation-31956" />

### `secp256k1WithValidation`

`secp256k1WithValidation` : [`SignatureHex`](#type-da-crypto-text-signaturehex-12945) -> [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`PublicKeyHex`](#type-da-crypto-text-publickeyhex-51359) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate the SECP256K1 signature given a hex encoded message and a hex encoded DER formatted public key. Prior to
signature validation, validate the public key and check it is on the SECP256K1 curve.

<span id="function-da-crypto-text-secp256k1withecdsaonly-56908" />

### `secp256k1WithEcdsaOnly`

`secp256k1WithEcdsaOnly` : [`SignatureHex`](#type-da-crypto-text-signaturehex-12945) -> [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`PublicKeyHex`](#type-da-crypto-text-publickeyhex-51359) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate the SECP256K1 signature given a hex encoded message and a hex encoded DER formatted public key.

<span id="function-da-crypto-text-secp256k1-38075" />

### `secp256k1`

`secp256k1` : [`SignatureHex`](#type-da-crypto-text-signaturehex-12945) -> [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`PublicKeyHex`](#type-da-crypto-text-publickeyhex-51359) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate the SECP256K1 signature given a SHA256 hash of a hex encoded message and a hex encoded DER formatted public key.

<span id="function-da-crypto-text-numericviastringtohex-44461" />

### `numericViaStringToHex`

`numericViaStringToHex` : [`NumericScale`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-numericscale-83720) `n` => [`Numeric`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-numeric-891) `n` -> [`BytesHex`](#type-da-crypto-text-byteshex-47880)

<span id="function-da-crypto-text-numericviastringfromhex-60098" />

### `numericViaStringFromHex`

`numericViaStringFromHex` : [`NumericScale`](/appdev/reference/daml-standard-library/prelude#class-ghc-classes-numericscale-83720) `n` => [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) ([`Numeric`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-numeric-891) `n`)

<span id="function-da-crypto-text-bytecount-29784" />

### `byteCount`

`byteCount` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261)

Number of bytes present in a byte encoded string.

<span id="function-da-crypto-text-minbytes32hex-29458" />

### `minBytes32Hex`

`minBytes32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Minimum Bytes32 hex value

<span id="function-da-crypto-text-maxbytes32hex-56560" />

### `maxBytes32Hex`

`maxBytes32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Maximum Bytes32 hex value

<span id="function-da-crypto-text-isbytes32hex-1801" />

### `isBytes32Hex`

`isBytes32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate that the byte encoded string is Bytes32Hex

<span id="function-da-crypto-text-minuint32hex-58146" />

### `minUInt32Hex`

`minUInt32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Minimum UInt32 hex value

<span id="function-da-crypto-text-maxuint32hex-80016" />

### `maxUInt32Hex`

`maxUInt32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Maximum UInt32 hex value

<span id="function-da-crypto-text-isuint32hex-65583" />

### `isUInt32Hex`

`isUInt32Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate that the byte encoded string is UInt32Hex

<span id="function-da-crypto-text-minuint64hex-67161" />

### `minUInt64Hex`

`minUInt64Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Minimum UInt64 hex value

<span id="function-da-crypto-text-maxuint64hex-40555" />

### `maxUInt64Hex`

`maxUInt64Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Maximum UInt64 hex value

<span id="function-da-crypto-text-isuint64hex-49912" />

### `isUInt64Hex`

`isUInt64Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate that the byte encoded string is UInt64Hex

<span id="function-da-crypto-text-minuint256hex-23801" />

### `minUInt256Hex`

`minUInt256Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Minimum UInt256 hex value

<span id="function-da-crypto-text-maxuint256hex-58651" />

### `maxUInt256Hex`

`maxUInt256Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Maximum UInt256 hex value

<span id="function-da-crypto-text-isuint256hex-33362" />

### `isUInt256Hex`

`isUInt256Hex` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Bool`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-bool-66265)

Validate that the byte encoded string is UInt256Hex

<span id="function-da-crypto-text-packhexbytes-55939" />

### `packHexBytes`

`packHexBytes` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261) -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Pack a byte encoded string to a given byte count size. If the byte string is shorter than the pad
size, then prefix with 00 byte strings. If the byte string is larger, then truncate the byte string.

<span id="function-da-crypto-text-slicehexbytes-22633" />

### `sliceHexBytes`

`sliceHexBytes` : [`BytesHex`](#type-da-crypto-text-byteshex-47880) -> [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261) -> [`Int`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-int-37261) -> [`Either`](/appdev/reference/daml-standard-library/prelude#type-da-types-either-56020) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952) [`BytesHex`](#type-da-crypto-text-byteshex-47880)

Extract the byte string starting at startByte up to, but excluding, endByte. Byte indexing starts at 1.